Objective--The Health Services for the Elderly Act in Japan provides for general health check-ups. We looked for a correlation between the use of these check-ups by adults (40 or older) and demand for in-patient care of the elderly (70 or older).Design and setting--For this survey, a questionnaires was mailed in 1988 to all 509 Japanese cities with a population of 30,000-199,999. They were all returned with data for 1983 and 1986.Measurements--We calculated correlation coefficients between the logarithmic rates of use of general health check-ups and logarithmic mean bed-days by size of cities and certain categories of number of beds per population. To compare relative changes rather than absolute ones, we analyzed correlation between improvement indices (ratio of change from 1983 to 1986 times the percentage of achievement of a goal or national mean.)Main results--In cities with relatively high rates of use of health check-ups, both the mean bed-days and the mean in-patient fee tended to be low. Correlation coefficients between the logarithmic rates of use of check-ups and logarithmic mean bed-days were all minus values by sizes of cities and certain categories of number of beds. There tended to be more correlation for higher rates of use in 1983 of these check-ups, and the correlation was significant for the rate of 60% or more.Conclusions--Strong health-service programs for starting in middle age decrease the demand for in-patient care of the elderly. In a single year, an increase in the rate of use from 25.5% to 27.6% was calculated to have saved 2.26 million bed-days for the total of 8.5 million of elderly persons.